McLaren 'intends' to retain same driver line-up

Alonso returned to the squad on a long-term deal at the start of the year while McLaren has an option to keep Button for 2016.

Speculation over Button's future has been heightened by the presence of test and reserve driver Kevin Magnussen, as well as GP2 championship leader Stoffel Vandoorne, both of whom are McLaren young drivers.

While expecting to hold on to Button, Boullier is optimistic that McLaren can find Formula 1 seats for Magnussen and Vandoorne.

"As far as we are concerned, McLaren have only two cars, only two race seats and we have two world champions and we intend to keep them so far," Boullier said at the Italian Grand Prix.

"We expect the four of them to race; it's a luxury problem to have four good drivers. Kevin and Stoffel are very good.

"Both of them we expect to race in Formula 1 and if we can't fit or accommodate them we will do our best to make sure they can race next year."